Problem: $\begin{cases} f(1)=25 \\\\ f(n)=f(n-1) \cdot \left(-\dfrac{1}{5}\right) \end{cases}$ $f(3)=$
Explanation: ${f(2)}={f(1)}\cdot\left(-\dfrac{1}{5}\right)={25} \cdot \left(-\dfrac{1}{5}\right)={-5}$ ${f(3)}={f(2)} \cdot \left(-\dfrac{1}{5}\right)={-5} \cdot \left(-\dfrac{1}{5}\right)={1}$ $f(3)=1$